On Wednesday 04 January 2012 01:54 AM, Scott Wood wrote:
On 12/28/2011 10:59 PM, Prabhakar Kushwaha wrote:
IFC NAND Machine calculates ECC on 512byte sector. Same is taken care in
fsl_ifc_run_command() while ECC status verification. Here buffer number is
calculated assuming 512byte sector and same is passed to is_blank.
However in is_blank() buffer address is calculated using mdt->writesize which is
wrong. It should be calculated on basis of ecc sector size.

Also, in fsl_ifc_run_command() bufferpage is calculated on the basis of ecc 
sector
size instead of hard coded value.

Signed-off-by: Poonam Aggrwal<poonam.aggr...@freescale.com>
Signed-off-by: Prabhakar Kushwaha<prabha...@freescale.com>
---
  git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc.git (branch next)

  Tested on P1010RDB

  drivers/mtd/nand/fsl_ifc_nand.c |    6 ++++--
  1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
index 8475b88..2df7206 100644
--- a/drivers/mtd/nand/fsl_ifc_nand.c
+++ b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -191,7 +191,9 @@ static int is_blank(struct mtd_info *mtd, unsigned int 
bufnum)
  {
        struct nand_chip *chip = mtd->priv;
        struct fsl_ifc_mtd *priv = chip->priv;
-       u8 __iomem *addr = priv->vbase + bufnum * (mtd->writesize * 2);
+       int bufperpage = mtd->writesize / chip->ecc.size;
+       u8 __iomem *addr = priv->vbase + bufnum / bufperpage
+                                       * (mtd->writesize * 2);
        u32 __iomem *mainarea = (u32 *)addr;
        u8 __iomem *oob = addr + mtd->writesize;
        int i;
This function should only be checking one ECC block, not the entire
page.  The caller is responsible for passing in the appropriate buffer
numbers.

I think what the current code needs is for (mtd->writesize * 2) to be
replaced with chip->ecc.size, and for the calling code to multiply the
starting bufnum by two.

    Got your point :). I will take care in next patch version.


@@ -273,7 +275,7 @@ static void fsl_ifc_run_command(struct mtd_info *mtd)
                dev_err(priv->dev, "NAND Flash Write Protect Error\n");

        if (nctrl->eccread) {
-               int bufperpage = mtd->writesize / 512;
+               int bufperpage = mtd->writesize / chip->ecc.size;
                int bufnum = (nctrl->page&  priv->bufnum_mask) * bufperpage;
                int bufnum_end = bufnum + bufperpage - 1;

Currently this driver always sets chip->ecc.size to 512.  If we want to
support other ECC block sizes that future versions of IFC may have, can
we calculate bufperpage during chip init (similar to bufnum_mask) to
avoid the runtime division?  It's probably not huge overhead compared to
everything else we do per NAND page transfer, but still...


  Yes. I agree.
   We are working on this in order to support new controller version.

--Prabhakar


_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Reply via email to